Backpack



FIG. 1 is a perspective view of a backpack;

FIG. 2 is a front view of the backpack shown in FIG. 1;

FIG. 3 is a rear view of the backpack shown in FIG. 1;

FIG. 4 is a right side view of the backpack shown in FIG. 1;

FIG. 5 is a left side view of the backpack shown in FIG. 1;

FIG. 6 is a top view of the backpack shown in FIG. 1; and,

FIG. 7 is a bottom view of the backpack shown in FIG. 1.

The portions of the backpack and any exemplary environment shown in broken lines are for illustrative purposes only and form no part of the claimed design. 

I claim the ornamental design for a backpack, as shown and described. 